Study on purification and ultrastructure of a baculovirus in Penaeus chinensis

A kind of baculovirus was isolated from the cephalothorax homogenate of sick or morbid Penaeus chinensis by differential centrifugation and density gradient centrifugation.Electron microscopic examination of ultrathin section of the gills,stomach and mid-gut tissues also revealed the presence of rod-shaped baculoviral particles with the same size in the affected cell nuclei,where most of the virions arranging in cluster assembled and caused a series of cytopathic changes.The virion covered with bilaminal envelope was 320-400 nm×100-130 nm in size,whereas the nucleocapsid ranged in size of 250-300 nm in length and 70-100 nm in breadth respectively.No nuclear polyhedron or granulin occlusion bodies have been found in cells.According to the principle of viral classification,this newly found virus could probably belong to the non-occluded subgroup oI insect baculoviridae,i.e.,C subgroup baculovirus.